Recommendation ITU-R P.676-12 (08/2019) Attenuation by atmospheric gases and related effects
Foreword
Policy on Intellectual Property Right (IPR)
Scope
Annex 1  Line-by-line calculation of gaseous attenuation
1 Specific attenuation
2 Path attenuation
     2.1 Terrestrial paths
     2.2 Slant paths
          2.2.1 Non-negative apparent elevation angles
          2.2.2 Negative apparent elevation angles
          2.2.3 Space-Earth Earth-space reciprocity
          2.2.4 Atmospheric bending
          2.2.5 Excess atmospheric path length
3 Dispersive effects
4 Downwelling and upwelling microwave brightness temperature
     4.1 Downwelling microwave brightness temperature due to gases
     4.2 Upwelling microwave brightness temperature due to gases
5 Slant path attenuation using vertical atmospheric profiles
Annex 2  Approximate estimation of gaseous attenuation  in the frequency range 1-350 GHz
1 Specific attenuation
2 Path attenuation
     2.1 Terrestrial paths
     2.2 Slant paths
          2.2.1 Elevation angles between 5° and 90°
               2.2.1.1 Earth-space paths
               2.2.1.2 Inclined paths
          2.2.2 Elevation angles between 0 and 5 degrees
               2.2.2.1 Earth-space paths
               2.2.2.2 Inclined paths
     2.3 Zenith path water vapour attenuation